This invention relates generally to keyboard, video and mouse switches, commonly known as KVM switches, wherein at least one workstation is coupled to the KVM switch for operation of the switch, the workstation also connectable via the KVM switch to one of a plurality of computers, and particularly to such a KVM switch incorporating power control means so that an operator at the workstation may control electrical power to each of the computers.
Conventionally, and referring to FIG. 1, prior art keyboard, video, and mouse (KVM) switching units, as illustrated by KVM unit 10, allow signals from a workstation or console 26 generally comprising a keyboard 12, mouse or other digital pointing device 14 and video signals to monitor 16 to be selectively coupled to/from a plurality of computers 18, 20, 22, and 24. These KVM switches 10 are conventionally provided with a plurality of computer interface ports so that a plurality of computer keyboard, video and mouse connections may be made to the KVM switch. As such, and by way of the example, shown in FIGS. 1 up to 4 keyboard, video and mouse connections from respective computers may be made to a single KVM switching unit 10. This allows a user at therefor console 26 to operate and display video from any one of computers 18-24 via KVM unit 10. Computers 18, 20, 22, 24 are typically file servers or used in applications not requiring continuous connection to keyboards, mice, and monitors. KVM unit 10 may be provided with an OSD (ON SCREEN DISPLAY) user interface 27, which provides convenient visual means, such as a selection of pop-up or pull-down menus, by which the user may operate KVM unit 10. KVM switching circuitry 28 is used to control routing of keyboard, mouse and video signals between the selected one of computers 18, 20, 22, 24 and console 26.
Most, if not all, of the KVM units marketed today contain at least one KVM channel microprocessor 30 that routes keyboard and mouse data and clock signals to a selected one of computers 18, 20, 22, 24, and a main microprocessor 32 that controls operation of KVM unit 10. The KVM channel microprocessors 30 each control a video switch (not shown in FIG. 1) to connect or disconnect a selected or deselected computer""s video signals to/from an internal video bus that carries video signals from computers 18, 20, 22, 24 to monitor 16. Commands from main microprocessor 32 instruct channel microprocessors 30 as to when to activate or deactivate the video switch. Further, channel microprocessors 30 route data from computers 18, 20, 22, and 24 to main microprocessor 32.
Main microprocessor 32 passes keyboard and mouse signals from the selected one of computers 18, 20, 22, 24 to ON SCREEN DISPLAY interface 27, which serves as an interface for the user, typically by presenting the user with a series of menu screens from which to conveniently select from a variety of menu options that operate KVM unit 10. As stated, the OSD interface allows the user to view a variety of menu selections whenever he wishes to perform a switch, power control, or administrative function. In the case where the user is a supervisor, such as a system administrator, OSD interface 27 may be used to perform administrative functions such as assigning passwords and security levels to individual users. OSD user interface 27 is provided with an OSD main microprocessor 34, which is coupled to pass commands between keyboard 12, mouse 14 and KVM switch 28. Commands and responses passed on mouse and keyboard lines from keyboard 12 and mouse 14 allow OSD main microprocessor 34 to control the functions of KVM switch 28 and monitor its status. Video from KVM switch 28 passes through an OSD video circuit 36 which is controlled by an OSD video microprocessor 38 which is in turn controlled by OSD main microprocessor 34. OSD video circuit 36 normally passes video signals from KVM switch 28 to console video monitor 16. Upon activation of a menu, OSD video circuit 36 injects video signals which superimpose a menu or menus onto the video signals provided by KVM switch 28. OSD main microprocessor 34 is provided with program memory for storage of the interface program and menus required for operation of OSD main microprocessor 34, read/write memory (RAM), such as buffer memory for temporary storage of data, and non-volatile memory for permanent or semi-permanent storage of data such as the user""s preferences for xe2x80x9chotkeyxe2x80x9d sequences used to activate the KVM switch features and user names and passwords. Commands are received by OSD video microprocessor 38 from OSD main microprocessor 34, causing OSD video circuit 36 to activate or deactivate. Console keyboard 12 is used to enter data or selections presented by the pop-up menus. When the user is not a performing a switching, or administrative function the console video monitor and the console keyboard are used as a normal video monitor and keyboard attached to KVM switch 28.
The keyboard and mouse data and clock signals from console keyboard 12 and mouse 14 are received by OSD main microprocessor 34 and normally passed to KVM switch 28. Signals from computers 18-24 are normally passed via KVM switch 28 to console keyboard 12 and mouse 14. With respect to xe2x80x9chot-keyxe2x80x9d sequences, OSD main microprocessor 34 responds by commanding OSD video microprocessor 38 to activate a pop-up menu. Concurrently, keyboard and mouse data and clock signals from console keyboard 12 and mouse 14 are prevented from being passed to KVM switch 28 while the pop-up menu is active. Rather, any keyboard or mouse commands applied to OSD main microprocessor 34 are used to change the pop-up menu content or set configuration data according to the keyboard and/or mouse entries by the user.
In some devices of the prior art, AC power from a conventional power source is simply applied to computers 18, 20, 22, and 24 from a power distribution unit 40, as shown in FIG. 1. In other prior art devices, as shown in FIG. 2, a power switch 42 is conventionally coupled to AC power and to an ASCII terminal 44 coupled to a microprocessor 46 inside power switch 42. Microprocessor 46 in turn is coupled to energize or deenergize, through appropriate drivers, relays or solid state power switching devices 48, 50, 52, and 54, which in turn couples or decouples AC power to computers 18, 20, 22, and 24. Some applications of this type power control system provide a means for individually switching ON or OFF the AC power to computers 18-24 from a remote location, and to implement security options such as password protection.
Some of the drawbacks of these computerized power switches are that the ASCII terminal that controls the power switch is separate from the console controlling the KVM switch, meaning that space must be made available for both the console and the ASCII terminal. Also, the menu options or other control scheme of the OSD interface is invariably different from the menu selections of the computerized power switch. This requires the operator to be familiar with two computerized control schemes instead of one, which is inconvenient and may lead to errors in operation of the systems. Further, two separate computerized systems requires that passwords and other security protocols and data bases be duplicated.
With respect to power control switches that are not under microprocessor control, these power switches must be operated manually, which is inconvenient if the power switch is remotely located from the console 12 operating KVM unit 10. Also, power status of these manually operated switches cannot be checked from a central location. Further, since there are no security provisions in these manually operated switches, they may be operated by anyone.
In view of the foregoing, it is one object of the invention to provide a KVM switch having integrated power switching functions and control coupled to the same OSD interface that controls the console keyboard, video and mouse signals and which further uses the same password and other security features included in the OSD interface. Other objects and advantages of Applicants new KVM switch will become apparent upon a reading of the following specification.